Dryer Duct Cleaning Cleaning Out Dryer Duct Work (Inside Wall)?

Cleaning Out Dryer Duct Work (Inside Wall)? - dryer duct cleaning

I think it is blocked by the dryer duct work in my wall. This channel is of course a long way and a housewife watching her think that running through my roof! We could not find anywhere exaust on the outisde of the house. Now I need to get there, at least to the point where your elbows and some of that fluff out. What is the best way?